Total entropy change of an air flow in a nozzle

Example 3.1 Total entropy change of an air flow in a nozzle Air enters a nozzle at 400 K and 60m/s and leaves the nozzle at a velocity 346 m/s. The air inlet pressure is 300 kPa, while the pressure at the outlet is 100 kPa. Heat lost in the nozzle is 2.5 kJ/kg. Determine the total entropy change if the surroundings are at 300 K. 

Assume that air is an ideal gas. The nozzle operates at steady state. 

Energy balance for a nozzle at steady-state conditions yields 

Total entropy change = entropy changes of the air + entropy change of the surroundings 

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Example 3.1 Total entropy change of an air flow in a nozzle... 

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